ImageGadget : Set alpha correctly even when soloing channel
ImageGadget : Set alpha correctly even when soloing channel

GafferHQ/gaffer,GafferHQ/gaffer,andrewkaufman/gaffer,johnhaddon/gaffer,GafferHQ/gaffer,johnhaddon/gaffer,andrewkaufman/gaffer,GafferHQ/gaffer,johnhaddon/gaffer,andrewkaufman/gaffer,andrewkaufman/gaffer,johnhaddon/gaffer,GafferHQ/gaffer,andrewkaufman/gaffer,johnhaddon/gaffer